Obesity is defined as a condition in which energy sources such as carbohydrates and lipids have been over-accumulated as neutral fat in white adipocytes which are present in the living tissue, particularly in the subcutaneous adipose tissue or in the organ-peripheral tissue, resulting in an increase in body weight beyond the limits of skeletal systems or physiological functions. Among fat tissues, a visceral fat tissue, which builds up around an internal organ such as the mesentery, is thought to trigger abnormality in metabolism of carbohydrate or lipid, possibly resulting in lifestyle-related diseases such as heart diseases, arteriosclerosis, hypertension, diabetes, and fatty liver. When the aforementioned visceral-fat-induced obesity is associated with a plurality of arteriosclerosis risk factors including diabetes (carbohydrate metabolic disorder), hyperlipidemia (lipid metabolic disorder), and hypertension, such a condition is called metabolic syndrome. In metabolic syndrome, even when individual symptoms are not so severe, combination of a plurality of symptoms synergistically elevate possibility of onset of lifestyle-related diseases. Thus, metabolic syndrome patients are categorized into a high-risk group, and prevention and therapy of metabolic syndrome have been focused on.
As described above, accumulation of visceral fat is thought to be a considerably important factor for the onset of metabolic syndrome, lipid metabolic disorders (e.g., fatty liver and hyperlipidemia), carbohydrate metabolic disorders (e.g., diabetes), and cardiovascular diseases such as heart infarction and brain infarction. Therefore, for preventing or ameliorating these disease and pathological conditions, it is important to reduce accumulation of visceral fat.
Measures that have been proposed for preventing obesity include control of metabolism of lipid taken into the body, promoting burning of body fat, intake of a food or supplement which inhibits accumulation of fat, and administration of an anti-obesity agent in the medical field have been proposed. However, currently, there is only a few means to be effective for preventing and ameliorating obesity, from the aspect of safety and practical utility (e.g., satisfactory taste or processability).
Meanwhile, lactic acid bacteria have been used for many years in production of food, particularly milk products such as fermented milk, lactic acid bacterium beverage, and fermented butter. In addition, since lactic acid bacteria themselves have a variety of pharmacological activities including intestinal function control action, the lactic acid bacteria are used as materials for producing health food products, pharmaceutical products, etc. In previous reports of activity of lactic acid bacteria on fat accumulation, those belonging to genus Lactobacillus or the genus Lactococcus have been found to have a visceral-fat-reducing activity (Patent Document 1), and those belonging to the genus Lactobacillus gasseri have been found to have a fatty-liver-inhibitory action (Patent Document 2).
However, a lactic acid bacterium belonging to the genus Pediococcus has never been known to have a fat-accumulation-inhibiting activity and/or a fat-metabolism-improving activity.